The present disclosure relates to an organic electroluminescent device.
Recently, researches for developing flat display devices that is improved in a display quality and increased in a screen size have been making much progress. An electroluminescent device among the flat display devices is a self-emissive display device that can emit light itself. The electroluminescent device is designed to display a video image by exciting phosphors using carriers such as electrons and holes. The electroluminescent devices are classified into inorganic electroluminescent devices and organic electroluminescent devices. The organic electroluminescent devices is driven by a lower voltage of 5-20V compared to the inorganic electroluminescent devices driven by a voltage of 100-200V. That is, the organic electroluminescent device can be driven by a low voltage.
In addition, the organic electroluminescent device has a variety of excellent properties such as a relative wide viewing angle, a relatively high response speed, and a relative high contrast. Therefore, the electroluminescent device may be used as a pixel of a video display or a surface light source. Furthermore, since the electroluminescent device is relatively thin and has an excellent color quality, it is drawing attention as the upcoming flat display.
Meanwhile, passive matrix type organic electroluminescent devices that are not provided with separate thin film transistors (TFTs) have been widely used. Since the passive matrix type organic electroluminescent device has many limitations in power consumption, service life, and the like, an active matrix type, active matrix type organic electroluminescent devices have been developed as next generation displays requiring high resolution and large-sized screen.
However, since the active matrix type electroluminescent device is fabricated by attaching two substrates on which TFTs and organic electroluminescent layer are formed after forming a single seal line formed of ultraviolet sealant, moisture or gas may be easily infiltrated into the device.
In order to prevent the infiltration of the moisture and gas, a substrate with additional materials such as moisture absorption agent is formed inside the device. This causes increase a thickness of the device. Furthermore, there is a limitation in preventing the infiltration of the moisture using the moisture absorption agent.